Furnace pressure regulator



April 12, 1932. F BLEYER' 1,853,497

FURNACE PRESSURE REGULATOR Filed April 22, 1951 2 Sheets-Sheet 1 leg].

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CH4E4E5 f ELL-FEE) April 1932- c. F. BLEYER I FURNACE PRESSURE REGULATORFiled April 22, 1931 2 Sheets-Sheet 627448455 f. 525 542, M x M PatentedApr. 12, 1932 ATENT OFFICE CHARLES F. IBLEYER, OF LORAIN, OHIO FURNACEPRESSURE REGULATOR Application filed 41111122, 1931. Serial No. 532,097.

This invention relates to furnace pressure regulators and, while notlimited thereto, relates more particularly to means for and a method ofmaintaining a balanced pressure in open hearth furnaces and the like.

In the operation of a furnace it is desirable to maintain a balancebetween the furnace pressure and the atmosphere if possible in order toretain the hot gases in the furnace and toprevent the infiltration ofcold air.

The present invention provides a relatively simple mechanical controlapparatus for this purpose.

In the drawings: I Figure 1 is an elevation of apparatus constructed inaccordance with this invention.

Figure 2 is an enlarged fragmentary view of the furnace end of theapparatus.

Figure 3 isan enlarged sectional elevation throughthe remote ends of thesuction tubes.

Referring more particularly to the drawings the numeral 2 designates anopen hearth furnace which is provided with an opening 2 in its wallthrough which hot gases may escape from the furnace and air may enterthe furnace in accordance to unbalanced pressure between the interior ofthe furnace and the atmosphere.

A pipe 3 is mounted in the opening or port 2 and is provided with a portor orifice 3 in its side wall which communicates with 4 the furnace endof a suction tube 4 which is provided with a restriction wall or choke 5adjacent its other end remote from the furnace, having an orifice 5therein of the same diameter as the orifice 3.

The orifices 3 and 5 are only a fraction of the diameter of the pipe 4.

A second suction tube 40 has one end located adjacent the furnace end ofthe tube 4 but turned on so as not to receive any of the hot gasesissuing from the furnace through the pipe 3. The tube 40 is providedwith a restricted port or orifice 40 at its furnace end 45 and with arestriction wall or choke 41 adj acent its end remote from the furnace,having an orifice 41 therein. The orifices 40 and 41 are of the samediameter and are equal to the orifices 3 and 5 in the tube 4.

The tubes 4 and 40 have their ends remote from the furnace connected bya T-fittlng 42 with a suction conduit 7 which leads to a station 18. Thestation 18 includes a steam jet exhauster 17 controlled by a valve 20.It

will be understood that any standard form of exhauster may besubstituted for the ex hauster 17 if desired. The valve 20 isautomatically controlled by rods 21 and 21 connected to anoil sealedbell 19.

The bell 19 is located in a vessel 22 which is connected by a T-fitting25 to the conduit 7. The rod 21 carries a counterweight 23. If thesuction created by the exhauster 17, acting on the bell 19, overcomesthe combined weights of the bell and counterweight 23, the bell risesand the rods 21 and 21 operate the valve 20 to throttle the suction,thereby maintaining a constant suction in'the pipe 7 and on the coldends of the tubes 4 and 40.

The tubes 4 and 40 are provided with branches and 46, respectively,closely adjacent their ends remote from the furnace which are incommunication, respectively, with bells 47 and 48 mounted on theopposite ends of a balanced beam 49 and having their lower or open endssealed in oil in a housing 11. The balanced beam 49 is connected bylevers 80 and 31 to a valve 32 of a compressed air motor'13 which hasits piston rod 14 connected by a cable or rope 15 to the damper 16 inthe draft flue 16 of the furnace 2.

In operation, suction from the conduit or pipe 7 will draw gases or airfrom the tube 4 through the orifice 5 This suction will cause a flow ofgases or air through the inlet orifice 3 into the tube 4. The suction inthe tube 4 will increase until the same weight of gas or air enters intothe conduit 4 through the orifice 3 as is withdrawn through theorifice5. After this equilibrium is "established, the suction in thetube 4 remains con- I stant as long as the suction in the conduit orpipe 7 remains constant and the temperature of the gases or air flowingthrough the orifices of the tube 4 remains constant. The temperature atthe outlet orifice 5 is atmosoheric, and therefore ma be consideredconsta'ntfor practical purposes. The temperature at the inlet orifice3*, however, varies con-.

siderably as at times the hot gas from the furnace flows through theinlet orifice and at other times cold air, which is bein drawn into thefurnace, flows through tie inlet orifice.

Furnace gases and air have substantially the same density at atmospherictemperature but the gases, say at 2000 degrees Fahrenheit,

have only 21 per cent. of the density of atmospheric air. As aresult,m:uch less weight of gases enters the inlet orifice when hotfurnace gases are entering the tube 4 and, therefore, the suction in thetube 4 rises immediately and drops again when cold air enters. From theabove it will be readily understood tliat'the suction in the tube 4Varies in accordance with the temperature of the gaseous products drawninto said tube.

The second suction tube 40 receives atmospheric air at its furnace endand, therefore, the suction in this tube remains substantially constantat all times.

The furnace or inlet r end of the tube 40 is located adjacent thefurnace or inlet end of the tube 4 so'that the atmospheric air enteringthe tube will be of substantially the same temperature as thetemperature of the cold air entering the fur- "nace through the pipe 3,The radiation of heat from the furnace will have some effect on thetemperature of the air adjacent the furnace. Therefore, 1n order toproperly 7 balance the suction of the tubes 4 and 40', it is desirableto draw. atmospheric air of the same temperature through the tubes. Thesuction in the tubes 4 and 40' is communicated to the balanced bells 47and 48,

, itedthereto since various modifications may be made without departingfrom the scope of our invention, as defined in the appended claims.

I claim: 7 1. In a furnace pressure control the combination with afurnace having a port through which hot gases may escape when thefurnace is above atmospheric pressure and through which atmospheric airwill flow into the furnace when the furnace is operating belowatmospheric pressure, of a pair of suction tubes, one of said tubeshaving one end in communication with said port in said furnace and theother of said tubes having one end in close proximity to said port andpositioned so as not to receive the gases or air flowing through saidport, said suction tubes having their other ends remote from saidfurnace, a control apparatus consisting ofa balanced beam, a sealed bellon each end of said beam, one of said tubes being connected adjacent itsend remote from said fur- :nacetoone ofsaidbells and the other of saidtubes being connected adjacent its end remote from said furnaceto theother of said bells, a restricted orifice adjacent each end of each ofsaid tubes, means for providinga suction to the ends of each of saidtubes remote from said furnace whereby the gas or air flowing throughsaid furnace port will be drawn through the tube communicating with saidport and atmospheric air will be drawn through the other of said tubesand'the suction in the tube having the gas or air from said furnace portpassing therethrough varying in accordance with the temperature anddensity ofsaid gas and air so as to unbalance the suction in said bellsand rock said beam, and means operable by said beam for controlling thefurnacedraft.

2. The combination with a furnace having a port therein through whichhot gases-will issue when the pressure in the furnace is aboveatmospheric pressure, and through which atmospheric air will stream whenthe furnace is below atmospheric pressure, means for utilizing thedifferences in density of the gas and air flowing through said port topro vide a suction varying in accordance with said density, meansforrutilizing atmospheric air of substantially constant temperature anddensity to provide a suction of relatively constant value, and means forbalancing the suction provided by said first named means against thesuction provided by said second named means, and means operable by saidbalancing means for controlling the draft to said furnace.

3. .The method of automatically maintainin g balanced pressure in afurnacewhich consists in allowing hot gases fromthe furnace to issuefrom a port when the pressure in the furnace is above atmosphericpressure, and allowing cold air to stream into the furnace through thesame port when the furnace is below atmospheric pressure, drawing theair or gases flowing through said opening with constant suctionsuccessively through a series of two orifices at opposite endsof aconfined flow path thereby creatin differences in suction responsive tothe di erences in temperature and density of said gas or air, drawingatmospheric air successively through a series of two orifices atopposite ends of a second confined flow path so as to provide asubstantially constant suction between said orifices, said air beingdrawn through said orifices under the same head of suction as said airor gas from said furnace port, balancing the suction in said first namedconfined flow path against the suction in said second named confinedfiow path and utilizing the differences between said suctions to,control the draft in said furnace.

In testimony whereof, I have hereunto set my hand.

CHARLES F. BLEYER.

